METHOD OF FORMING INTERCONNECT HAVING STACKED ALIGNMENT MARK

摘要

A first film layer is formed over a substrate. A portion of the first film layer is removed to form a first alignment mark pattern and a first conductive layer is formed to fill the first alignment mark pattern to form a first alignment mark. A second film layer is formed and a portion of the second film layer is removed to form openings and to form a second alignment mark pattern. A second conductive layer is formed to fill the openings to form first conductive wires and to fill the second alignment mark pattern to form a second alignment mark. A third film layer and a hard mask layer are formed over the second film layer and a portion of the hard mask layer and the third film layer is removed to form via openings. A third conductive layer is formed in the via openings.